Growing of HgCdTe Heterostructures with in situ Ellipsometric Control
V. A. Shvets1, N. N. Mikhailov2, S. A. Dvoretskii2
1 Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences Novosibirsk State University
2 Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences
shvets@isp.nsc.ru, mikhailov@isp.nsc.ru, dvor@isp.nsc.ru
Keywords: molecular beam epitaxy, mercury cadmium telluride, heterostructures, IR photodetectors, ellipsometry, in-process control
Pages: 13-24
Abstract
A retrospective analysis of growing of multilayered and variband structures based on the mercury cadmium telluride compounds by the method of molecular beam epitaxy with ellipsometric control and methodical developments in the field of ellipsometry of inhomogeneous structures is presented. Calculations are performed, and solutions of direct and inverse problems for some cases important for practice are obtained. The high accuracy of determining the thickness and composition of the layers in growing heterostructures of nanometer-scale thicknesses is demonstrated. In some cases, it is proposed to use the relative derivative of ellipsometric parameters measured in the course of growing the structure to increase the accuracy of solving the inverse problem. This procedure allows the profiles of the optical constants of structures with gradient compositions to be determined. Theoretical calculations for periodic layered structures are performed, and the possibility of their controlled growing is demonstrated in experiments.
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